PIC MicroChip


Thread Starter


Currently I’m doing a project by using a PIC microcontroller 16F87X series to control a DC motor (speed & position). Meanwhile I must design a communication protocol which allow user to change these speed & position settings as they like. Can anyone help me on this?
I think that MODBUS protocol is good for this purpose, becouse a lot of control networks have implementation of this protocol.

Modbus is, by far, the most common, robust, and CHEAPEST solution. It is fairly easy to implement. Email me if you have any questions.

MODBUS protocol will be a better solution for your purpose, because it is very easy to implement and its memory requirements are also less enables it to port to any of the embedded systems. For more details, check http://www.sunlux-india.com.


Jim Woodward

Check out our Accelus digital servo-amplifiers.
Using the PWM output of the PIC chip you could control torque or velocity of a motor with encoder feedback. Or you could output a pulse train to the amplifier that can operate the motor like a stepper motor. Velocity and acceleration limits in the amplifier mean that a constant-frequency pulse burst would produce a profile with controlled accel/decel and velocity.
Or you could use RS-232 commands to produce a motion profile.
None of the above require a proprietary comm-bus like Modbus, and all are quite simple to implement in hardware.

dear friend

I think you are working on position control of DC motors. I was able to understand the speed control, but how can we do position control? would you please explain the dynamics of that? Do you for positioning purposes make angle (theta) as position parameter or distance in mm or Meters? please do explain how you intend to do. if you have any idea of algorithms please tell me.

with regards
mohd sulaiman